Apparatus for welding tubes



March 7, 1933. F w, wElR 1,900,376

APPARATUS FOR WELDING TUBES Or iginal Filed July 14, 1951 s Sheets-Sheet1 INVENTOR Ma L F. W. WEIR APPARATUS FOR WELDING TUBES Margh 7, 1933,

Original Filed July 14, 19.}1 3 Sheets-She et INVENTOR 4 WW @QDM KQ/DMarch 7, 1933. F. w. WEIR APPARATUS FOR WELDING TUBES Original Filed-July 14', 1931 s Sheets-Sheet s INVENTOR W 40 Low,

Fatented Mar. 7, 1933 mam .ssict FRED W. WEIR, F PITTSBURGH,PENNSYLVANIA APPARATUS FOR WELDING TUBES original application filed July14, 1931, Serial No. 550,857. Divided and this application filed January9, 1932. Serial No. 585,720.

My invention relates to apparatus for welding. One of its principalobjects is to raise the temperature of the edges or surfaces to bewelded together to a higher temperature than the edges or surfaces areusually heated preliminarily to the seam-closing steps of weldingoperations. Another object is to prepare the said edges or surfacesprior to the seam-closing steps so as to ensure that the 1o welded edgesor surfaces shall be freed from oxides, scale, and other foreign matter.A further object is to remove scale or other foreign matter from one orboth surfaces of ofjects as they are being welded. @ther objects appearhereinafter.

This application is a division of my application Serial Number 550,657,filed July 14, 1931.

Referring to the accompanying drawings,

Fig. 1 is a plan view of fragments of a furnace and a butt-weldingdraw-bench associated with one form of my invention, parts being brokenaway and omitted; Fig. 2, a side view of Fig. 1, but showing the furnace2 in vertical longitudinal section; Fig. 3, an end elevation of one formof a blower head for directing pre-heated gas into contact with the saidskelp just prior to the seamclosing step; Fig. 4:, a plan view of Fig. 3

without the lateral supports for the head; Fig. 5, a section on the line5-5 on Fig. a; Fig. 6, a section on the line 6-6 on Fig. 5; Fig. 7, aplan view illustrating my invention as applied to the making oflap-welded tubes,

many parts being omitted; Fig; 8, a side view of Fig. 7 Fig. 9, anenlarged cross-section of the pipe 45, the section being taken at theleft of the bell 47 in Fig. 7, the bell being indicated by dotted lines,and Fig.10, an enlarged plan view showing the relative arrangement ofthe skelp being welded and the nozzle of the blower.

While my invention may be illustrated as applied to the securingtogether of the adj acent edges or surfaces of the seam or differentobjects irrespective of the shapes or cross sections of the objects, Ihave elected to illustrate the same as applied to the manufacture ofbutt-welded and lap-welded tubes.

59 Referring first to Figs. 1 to 6, 11 designates a front end wall of askelp-heating furnace 12 having the skelp-discharge opening 13.

14 designates the portion of a draw-bench adjacent to the wall 11 of thefurnace. The draw-bench is provided with the weldingbell 15 throughwhich the skelp, one being shown at 16, is withdrawn from the furnaceand formed into a butt-welded tube, a portion of which is indicated at17 at the right of the bell. The apparatus thus far described is old andwell known and need not be further described.

The draw-bench carries the two parallel head-blocks18 arranged at rightangles with the furnace wall 11 and spaced apart so that the weldingbell lies between them. The head-blocks have the opposed verticalrecesses 19 in which the ends 20 of the blowerhead 21 have limitedvertical travel. The ends 20 rest on the vertical springs 22 seated onthe bottomwall 23 of the recesses. The ends 20 have openings 24 in whichvertical bolts 25 stand, the boltsstanding also in the bottom walls 23to which they'are secured by the nuts 26. The nuts 27 are screwed on theupper ends of the bolts 25 to limit the upward movement of theblower-head.

The upper face of the blower-head has a transversely upwardly-openchannel 28 through which the skelp 13 travels, the vertical sides 31 ofthe channel constituting guides for edges of the skelp. The lower faceof the skelp rides on the upper surfaces of two series of ribs 29 at thebottom of the channel 28 and adjacent to the sides 31 thereof, the twoseries of ribs being separated by the upwardly-open passage 30 below theskelp 16. The upper edges of these ribs 29 are inclined downwardly andtoward the adj acent sides31 so as not to engage the lower face of theskelp adjacent to its edges.

The blower-head 21 contains a'chamber 32 provided in its lower wall withthe inlet pipe 33 for pro-heated fluid, such as air, for example. Thereare a number of outlet ports 34 in the sides 31 through which thepreheated fluid is directed into the channel 28 and against the edges ofthe skelp 16 therein. The ports 34 are vertically elongatedsufficientlyto direct the fluid against the upper and lower faces of the skelp aswell as against its edges. The channels 35 between .the ribs 29 conductsome of the fluid beneath the skelp and into the upwardly-open passage30 lying transversly of the blowerhead and in the bottom of the channel28. The passage 30 lies between the opposing in ner ends of the ribs 29.The ribs 29 and consequently the channels 35 are inclined so as todirect the heated fluid toward the direction from which the skelp ismoving, the normal direction of movement of the skelp being indicated onFigs. 1, 2, and 4 by the arrow 36.

If desired, the blower-head 21 may have a separate channel 32 providedwith outlet ports 37 at the side thereof toward the furnace to direct aselected fluid, such as superheated steam, against the lower face of theskelp 16 before it reaches the welding-bell 15. The pipe 33 conducts thesteam to the chamber 32'. The ports 37 are inclined so as to direct thefluid diagonally against the skelp and to blow any scale or otherforeign matter on the lower edge of the skelp toward the furnace or awayfrom the bell. On Figs. 1 and 2, 38 designates a pipe for conveyingsuperheated steam to the nozzle 39 which opens directly above the upperface of the skelp just before it reaches the bell 15, the nozzle beinginclined downwardly and toward the furnace or the direction from whichthe skelp is moving so as to blow any scale or the like toward thefurnace or so that it will not enter the bell with the skelp.

In the practice of this invention with the butt-welding apparatus, theskelp are heated and drawn in the usual well known or other manner, thefiat skelp 16 being drawn one .by one from the furnace through thewelding-bell by which the skelp is caused to take a tubular form and theheated edges thereof are pressed together to form a welded seam from oneend of the resultant tube to'the .other. Simultaneously with the drawingoperation superheated air under pressure is admitted to the chamber 32and impinges against the edges of the skelp and the upper and lowerfaces thereof, more particularly, those parts of the faces adjacent tothe edges of the skelp.

The gaseousfluid blown against the skelp from the blower-head is airwhich contains approximately 23% oxygen, the remainder being principallynitrogen. As the blast of pre-heated air strikes the heated edges of theskelp during welding operations, the oxygen because of its great afinityfor carbon and manganese contained inthe skelp has a tendency to unitetherewith to support combustion which results in a localized in- [Acrease in temperature. To a degree, the inert or non-reactiveconstituent of the air,

nitrogen, has atendency to reduce temperamo em tures as it consumes heatfrom the skelp, particularly in cases where the blast is atapproximately atmospheric temperatures. Not only is it desirable tomaintain a welding temperature or actually increase the temperature atthe weld, but also it is desirable to direct a blast of considerableintensity in order to render more eflicient the scavenging effect of thesame. It is also desirable to control, as by the valve 40 in the pipe 33or by any other eflicient means, the amount of oxygen directed to theedges of the skelp to be Welded in order to reduce the decarburizingeffect resulting from combustion because the carbon and manganeseconstitutents of the metal have amarked influence on the strength of thefinished product. By increasing the intensity of the blast atatmospheric temperature, it has been observed that the increased volumeof nitrogen has a chilling effect which led to the development of thisinvention wherein the air is required to be pre-heated to a relativelyhigh temperature in order to ofi'set the neutralizing effect of thenitrogen and at the same time intensify the blast without introducing anexcess of oxygen. The heating of the air to a high temperature reducesits density and causes less oxygen .to impinge against the skelp, otherconditions remaining unchanged.

The combustion of oxygen and carbon and also oxygen and manganese tendstora'ise the temperature at the weld to a sufiiciently high degree forwelding so that the heating furnace for the skelp may be operated at aslight- 1y lower temperature. By pre-heating the air to a hightemperature the deterimental chilling effect of the nitrogen constituentin the air is practically eliminated because under these conditions itwill draw little or no heat from the skelp.

Referring now to Figs. 7 to 10, I have shown a pair of housings 42inwhich the two welding or closing rolls 43 are journalled. 44 designatesthe usual mandrel positioned in the roll-pass and over which the tubularskelp 45 is passed while the heated lips 46 of the tubular skelparepressed together between the rolls on the outside of the skelp andthe mandrel on the inner side thereof so as to form a welded seam on theupper side of the tube. As the skelp 45 passes through the guide bell 47on its way to and through the rolls 43, astream of pre-heated air underpressure is directed against the lips or edges 46 of the skelp This airis directed to the said edges by the nozzle 48 arranged at such an angleas to direct the air into the space between the edges and against thesame and also against the advancing movement of the skelp which travelsas indicated by the arrow thereon. The function of the pre-heated air isthe same in the lap-welding process as in the butt-welding processhereinbefore described.

I claim 1. In an apparatus for welding together the heated edges of ametalic strip, a blowerhead having a channel through which the strip isfed, lateral ports in the head opposite the edges of the strip, achamber in the blower-head with which the ports communicate, and meansto supply highly heated air under pressure to the chamber, the bottom ofthe channel having transverse ribs on which the strip rests, there beingtransverse passages between the ribsrto conduct the said air from theports into contact with the lower face of the strip near its edges.

2. In an apparatus for welding together the heated edges of a metallicstrip to form tubes, a blower-head having a channel through which thestrip is fed, lateral ports in the head opposite the edges of the strip,

a chamber in the blower-head with which the ports communicate, and meansto supply highly heated air under pressure to the chamber, the bottom ofthe channel having transverse ribs on which the strip rests, there beingtransverse passages between the ribs to conduct the said air from theports into contact with the lower face of the strip near its edges, theouter ends of the ribs being spaced below the edges of the strip.

3. In an apparatus for welding together the heated edges of a metallicstrip to form tubes, a blower-head having a channel through which thestrip is fed, lateral ports in the head opposite the edges of the strip,a

chamber in the blower-head with which the ports communicate, and meansto supply highly heated air under pressure to the chamber, the bottom ofthe channel having transverse ribs on which the strip rests, there beingtransverse passages between the ribs to conduct the said air from theports into contact with the lower face of the strip near its edges andthe ribs being inclined horizontally to direct the air blast away fromthe seamclosing instrumentality'.

In testimony whereof, I hereunto afl'ix my signature.

FRED w. WEIR.

